166 CLINICAL DIAGNOSTICS. 



e. The color of the feces is due to admixtures of bile, 

 coloring matter in the food (chlorophyll in herbivora, haem- 

 aglobin in carnivora) and secretions. An admixture of frag- 

 ments of bone, in dogs, produces a light gray color. An 

 exclusive milk diet produces yellow feces (bile) ; green fod- 

 der produces a greenish hue ; oats, straw and timothy hay 

 produce a yellowish brown color; corn, beans, rye (especially 

 when coarsely ground) produce a gray or yellowish gray 

 color. In cattle the diet is much more varied than in the 

 horse, consequently it is difficult to determine a normal color. 

 It varies from a distinct green (in pastured animals) to lighter 

 and darker shades of endless variety. Concentrated foods 

 (Kraftf utter) tend to produce a more grayish color. 



The following morbid changes may be observed: 



The longer the ingesta are retained in the intestine the 

 darker they become. After continued constipation the feces 

 of horses and cattle assume a blackish brown, peat-like color. 



A decreased admixture of bile (icterus) produces a gray, 

 or light gray color resembling clay. Admixtures of blood 

 produce a red, brownish red or chocolate color, sometimes 

 almost black. A thorough admixture of the blood with the 

 evacuated contents points to the occurrence of a hemorrhage 

 in the anterior portions of the intestinal tract (hemorrhagic 

 enteritis, dysentery, etc.). If the hemorrhage occurred in 

 the rectum the blood adheres in the form of streaks or clots. 



Discolorations are produced by catarrhal and inflam- 

 matory affections. In dysentery of calves the feces are gray 

 or grayish white. Some medicines produce specific colora- 

 tions of the feces : iron produces a black, calomel a green 

 color. 



f. Covering of the feces. In herbivora the feces are 

 covered with a thin pellicle of mucus which gives them a 

 shiny appearance. This coating of mucus increases or de- 

 creases in thickness as the time during which the feces are 

 retained in the intestine is increased or decreased. In intes- 



